The first known census was taken by the Babylonians in 3800 BC, over 5000 years ago. Records suggest that it was taken every six or seven years and counted the number of people and livestock, as well as the amount of butter, honey, milk, wool and vegetables. One of the earliest documented censuses was taken in 500-499 BC by the Persian Empire's military for issuing land grants, and taxation purposes.

Rome conducted censuses to determine taxes. The word 'census' has its origins from ancient Rome, coming from the Latin word 'censere', meaning ‘estimate’. The Roman census was the most developed of any recorded in the ancient world and it played a crucial role in the Roman Empire. The Roman census was carried out every five years. It provided a register of citizens and their property from which their duties and privileges could be listed.

The United States Constitution mandates that the census be taken at least once every ten years, and that the number of members of the United States House of Representatives from each state be apportioned accordingly. Census statistics are also used for apportioning federal funding for many social and economic programs.

The first U.S. Census was conducted in 1790 by Federal marshals. Census takers went door to door and recorded the number of people in each household, along with the name of the head of the household. Slaves were not counted as one person, but for apportionment purposes each counted as only three-fifths of a citizen. American Indians, being neither taxed nor considered during apportionment, were not counted in the census until the early 1900's.

Indexes to some of the U.S. Censuses have been produced over the years, making the process of searching old census records much easier. Some indexes of census records have been produced by amateur volunteer genealogists. Due to the sheer volume of information, and the methods involved, the indexing is sometimes limited to the head of household.

While valuable, indexes produced from these censuses can be very hard to use. The original census records from this era were completed by hand by census enumerators; this leads to problems in handwriting recognition and variations in spelling of surnames within the original documents.

Every effort has been made to translate these census accurately. If a spelling error exists in the census, it is translated the same into these charts.